hi again everyone, the original owner put a 3" cat back system by "fat pipes custom exhausts" in kallangur qld, once I got it I put a 100cell cat on it to increase flow, but the whole system seems to be holding me back in power. I have done injectors, hdi cooler, pod off turbo and tune but am only getting 293rwkw at 14psi. Car is bf mk1 6sp man.

My question is does anyone know these exhaust guys?? And also would putting a larger dump pipe on help me out?? Or can an exhaust shop chop and change mufflers etc to increase flow??

Sorry for long post, I'm thinking the 3" is the major problem but don't wanna fork out cash for a new system.

A 3" is a bit small for that power. I'm guessing you'd have no problem making 300 with a 3.5" exhaust.

A larger dump would help too but isn't necessary.

Yeh I would love to get a 3.5 system but don't wanna fork out the cash, this current system has two mufflers so I was thinking maybe an exhaust guy could take one out?? Although it's pretty loud already, anyone got any ideas.... or anyone in need of getting rid of there standard exhaust?? May solve my issue.... Cheers

I probably wouldn't touch it if its already pretty loud and I'm guessing if an exhaust shop made it, it would have high flow mufflers in it.

From memory, I think the standard exhaust flows more than a 3" system but a 3.5" would be an upgrade.

Maybe have a look around for second hand systems or see if someone want to swap you for there standard system.

A standard exhaust sounds like it would definitely outflow this.

If your exhaust already has a hiflo cat and won't go over 300kw its majorly restrictive.

As a guide, a highflow cat maxes out at 310-320, and a 4" dump and Cat is good for 350-360. In otherwise stock exhausts.

Edited October 3, 201115 yr by Henz

Henz, ok cool, so should I be looking for a standard exhaust catback?? I do no that the current one has a 3" single cat, would that match up to a stock system??

Yep.

Wats the size of the standard cat? Mime being 3" wouldn't cause any greif??

the standard cat is 3" in/out.

Thanks henz, is there any good value systems similar to stock but with good tone?? There are a few eBay systems that are designed around the stock system but say they "sound great" ........ Anyone had experience with any of them??